Application of Automatic Potentiometric Titration in Determination of Total Alkalinity in Water
This paper compared and analyzed the methods of manual titration and automatic potentiometric titration to detect the total alkalinity in water.The total alkalinity of blank samples,quality control samples and different types of actual water samples were tested.All test results were within the test requirements and the test results were reliable.Detection of blank samples calculated the detection limit of manual titration method was 2.4 mg/L and the determination limit was 9.5 mg/L.The detection limit of automatic titration was 0.5 mg/L,and the determination limit was 2.1 mg/L,which was significantly lower than that of manual titration.For the detection of quality control samples of different concentrations,the relative standard deviation of automatic potentiometric titration was less than or equal to 0.46％,and relative error was less than or equal to 0.22％.The relative standard deviation of manual titration was less than or equal to 1.46％,and relative error was less than or equal to 2.79％.Parallel double-sample analysis of actual samples showed that the relative deviation of automatic potentiometric titration was from 0.05％to 0.43％.The relative deviation of the manual titration method was from 0 to 2.99％,which indicated that the automatic potentiometric titration method had better precision and accuracy,and the detection results were more stable.The paired t-test was performed on 33 groups of actual water samples,and the result was P=0.146(＞0.05),indicating that there was no significant difference between the two methods.The relative deviation of the detection results of different personnel by manual titration method was from 0.30％to 2.03％,and the personnel deviation was obvious.The recovery rates of water samples with different turbidity was from 90.0％to 108.0％by manual titration and from 95.8％to 104.2％by automatic potentiometric titration.The relative deviations between the measured results of water samples below 55 NTU was less than 3.7％by manual titration and less than 1.5％by automatic potentiometric titration.Whether it was shake well or not has not has no significant effect on the test results.Compared with the manual titration method,which is easily affected by factors such as the proficiency of detection personnel,professional technical level,and color sensitivity,the automatic potentiometric titration method can take into account the accuracy and work efficiency,and realize intelligent detection.The field of drinking water needs to fill the gap in the national standard method of total alkalinity as soon as possible.
total alkalinityautomatic potentiometric titrationmanual titrationhigh turbidity water sampleintelligent detection
国家科技期刊平台
NSTL
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